Hello all,

I wrote this program to work out monthly payment for personal loan. Say, you borrow 15000 (principal) at 7.50% APR for 4 years?

So my formula is (maybe wrong):-

1. months = 4 * 12;

2. interest = principal * 7.50 / months;

3. monthlypayment = (principal + Interest) / months;

My monthly payment comes out as 361.38, is this correct?

What is correct formula to do this?

Here is my program, just in case you want to see it. Thanks.

Code:

// Calculating loan payment/interest
#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main()
{
char again;
do
{
system("CLS");
double amount, //amount per month
principal, //loan amount
rate, //interest rate
interest, //total interest
months, //months
years, //years term
totalpayment;
// set the floating-point number format
cout << setiosflags( ios::fixed | ios::showpoint )
<< setprecision( 2 );
cout << "Enter amount of loan: ";
cin >> principal;
cout << "Enter rate ( APR % ): ";
cin >> rate;
cout << "Enter number of years: ";
cin >> years;
//some calculation
months = years * 12;
interest = principal * rate / months;
amount = (principal + interest) / months;
totalpayment = principal + interest;
//display
cout << endl << "LOAN CALCULATION:";
cout << endl << "=================" << endl;
cout << "Total Loan : " << setw( 8 ) << principal << endl;
cout << "Rate APR % : " << setw( 8 ) << rate << endl;
cout << "Total years : " << setw( 8 ) << years << endl;
cout << "Total interest : " << setw( 8 ) << interest << endl;
cout << "Monthly payment : " << setw( 8 ) << amount << endl;
cout << "Total Payment : " << setw( 8 ) << totalpayment << endl << endl;
cout << "Again y/n? ";
cin >> again;
} while (again == 'y' );
return 0;
}